1. Field of the Invention
The present invention generally relates to a hybrid imaging apparatus integrating functions of multiple types of imaging apparatuses, such as a photo-copier, a printer, a facsimile machine, and other imaging devices, and to a print control method for such a hybrid imaging apparatus.
2. Description of the Related Art
In recent years, a so-called multi-function peripheral, in which various types of imaging functions (e.g., printing, photocopying, facsimile, etc.) are provided in a single apparatus, has been known. Such a multi-function imaging apparatus is also referred to as a hybrid imaging apparatus. In a hybrid imaging apparatus, a display, a printing unit, an optical scanner, an image-forming unit, and other units (collectively referred to as “multi-function peripherals”) are accommodated in one housing. In addition, various different applications, such as a printer application, a photocopy application, and a facsimile application, are installed in the apparatus corresponding to the respective functions. By switching among these applications, the hybrid imaging apparatus can accomplish multiple jobs requested by the multi-function peripherals.
In the conventional hybrid imaging apparatus, the applications operate independently without a unified rule. Each application produces an execution request independently, and supplies the request directly to the engine, as illustrated in FIG, 1. For example, photocopy application 1100 determines the operation mode, such as a duplex copy mode or a simplex copy mode, and generates an execution request based on the determined mode. The execution request causes the associated hardware resources, via the engine 1001, to execute the request. The same applies to the printer application 1200 and the facsimile application 1300.
The engine 1001 is realized by, for example, firmware, including image memory manager 1002 for managing image information, waiting list controller 1003 for controlling the order of executing the requests, and device controller 1004 for controlling the associated device.
The conventional hybrid imaging apparatus with independently operating multiple applications has a problem when carrying out duplex print jobs from different applications. In general, an interleave technique is employed when carrying out two different duplex jobs from the same application for the purpose of improving the productivity. However, it is difficult for the conventional hybrid imaging apparatus to apply the interleave technique to duplex jobs from different applications. This will be explained with reference to FIGS. 2A through FIG. 2C.
If an ordinary interleave technique is applied to treating multiple duplex jobs from different applications, image data supplied from different peripherals (a photocopier and a printer in the example shown in FIG. 2A) should be processed as illustrated in FIG. 2A, in order to achieve a high productivity. Namely, image 2 from a printer is interleaved between image 1 and image 3, which are supplied from a photocopier. Similarly, image 5 from the printer is interleaved between image 4 and image 6, which are supplied from the photocopier.
In other words, images 1, 3, 4, and 6 are included in a print job requested by the photocopy application 1100 to the engine 1001, while images 2 and 5 are included in a print job requested by the printer application 1200 to the engine 1001. Images 1 and 3 are reproduced on both sides (i.e., the front and the back) of a sheet, respectively. Similarly, images 4 and 6 for page 2 of photocopy are reproduced on both sides of a different sheet. Images 2 and 5 from the printer are printed out on both sides of another sheet.
However, when the engine 1001 of the conventional hybrid imaging apparatus actually carries out the above-described interleaving, productivity is often lowered because it is not known when the execution requests will be issued from independently operating applications.
As illustrated in FIG. 2B, if simply applying the interleave technique to the conventional hybrid imaging apparatus, the engine 1001 first reproduces image 1 from the photocopy application 1100 on the front side of a sheet, then executes image 2 from the printer application 1200 on the front side of the next sheet. These two sheets remain in the apparatus, without being ejected, until the counterpart images 3 and 5 are reproduced on the back sides. Then, the engine 1001 reproduces image 3 from the photocopy application 1100, which is the counterpart of image 1, on the back side of the first sheet, and this sheet is ejected.
Next, the engine 1001 executes a print request for the second page of photocopy to reproduce image 4 on the front side of the third sheet. At this point in time, the second sheet and the third sheet, each of which bears an image only on the front side, are accumulated inside the imaging apparatus in this order. Accordingly, image 6 cannot be reproduced on the back of the third sheet until image 5 is reproduced on the back of the second sheet and until the second sheet is ejected. If the print request for image 5 produced by the printer application 1200 is delayed for some reason, the subsequent process stops. In this case, even if the print request for image 6 from photocopy application 1100 has reached the engine 1001, image 6 cannot be reproduced because of the existence of the second sheet on which back-side an image has not yet been reproduced. Consequently, undesirable time loss occurs, as illustrated in FIG. 2B, and the productivity is inevitably lowered. Furthermore, the third sheet may hit the trailing edge of the second sheet, and cause a paper jam, depending on the type of the apparatus. Thus, the conventional hybrid imaging apparatus can not advantageously make use of the interleave technique for duplex print operations.
Instead, to avoid the above-described problem, the conventional hybrid imaging apparatus treats the print jobs independently when duplex print jobs are produced by different applications, as illustrated in FIG. 2C. The entire print job for photocopy (that is, images 1 through 4 in this example) is executed first, reproducing images on the front and the back of sheet alternately. During the execution of this print job, another duplex print job from the printer application 1200 is waiting. When the entirety of the photocopy job is finished, the print job with image data 5 and 6 produced by the printer application 1200 is then executed. With this method, the printing rate is reduced, and the multiple functions furnished in the hybrid imaging apparatus cannot be efficiently used. In fact, no attempt has been made so far to apply the interleave technique to the hybrid imaging apparatus to mix duplex jobs from different applications.
Meanwhile, Japanese patent laid-open publication No. 2000-0158972 discloses a technique in which if it is predictable that a first output job is to be interrupted, another job that is not likely to be interrupted is processed prior to the first output job. However, this technique is not addressed to a hybrid imaging apparatus involving different types of imaging applications. It is difficult for this technique to predict a possibility of interruption in duplex printing operations where print jobs from different imaging applications are mixed.
Japanese patent laid-open publication Nos. 2000-092257 and 2000-233550 disclose a technique for allowing the user to change priority of the reserved print jobs. These publications do not address a hybrid imaging apparatus. In addition, it is difficult for the user to determine how the priority is changed before interruption occurs. Changing the priority after the interruption does not solve the problem of falling of productivity in duplex printing operations at all.